Basics ⬇
[
Show Section Outline]
DESCRIPTION
- Mushroom toxicity is classified clinically based on the time of symptom onset.
- Lethal intoxication is associated with mushrooms producing initial symptoms more than 6 hours after ingestion.
- Caution must be exercised, however, because it is possible to develop symptoms before 6 hours and still have a lethal ingestion if more than one type of mushroom was ingested.
Mushroom/Toxin Groups that Typically Produce Symptoms Within 3 Hours of Ingestion
- The disulfiram-like group (certain species of Coprinus, Clitocybe, Boletus mushrooms) may produce a disulfiram reaction if alcohol is later ingested; this is most commonly associated with ingestion of Coprinus atramentarius ("inky cap").
- The muscarine group (among which are some species of Boletus, Clitocybe, Inocybe) produces muscarinic receptor stimulation: salivation, lacrimation, urination, defecation, and bronchorrhea.
- The ibotenic acid and muscimol group (some species of Amanita, Tricholoma, Panaeolus) causes alcohol-like intoxicated delirium accompanied by jerking movements.
- The hallucinogen group (species of the genera Conocybe, Gymnopilus, Panaeolus, Pluteus, Psilocybe, and Stropharia) causes hallucination; the chief toxins are psilocybin and psilocin.
- Psilocybe genus contains more than 100 species of small, brown, slender-stalked mushrooms, commonly found growing in piles of dung and fertilized grasses in moist areas all over the United States; they are especially common in the South.
- A classic feature of Psilocybe species (and of many other toxic mushrooms) is the development of blue-green color where it is injured or handled.
- The gastrointestinal irritant group causes repeated vomiting and diarrhea.
- This group is a catch-all for mushrooms that produce gastroenteritis but do not produce systemic signs or symptoms (besides dehydration), usually resulting in a benign clinical course; toxins are varied and mostly unknown.
- One of the most common species is Chlorophyllum molybdites; its juvenile form is often mistaken for the edible "shaggy mane," from which it may be distinguished by faint green gills and a green spore print.
Symptoms Noted More than 6 Hours After Ingestion
- The cyclopeptide group of toxins (present in a number of Amanita, Galerina, Lepiota, and Conocybe species) produce severe hepatic injury with a high fatality rate.
- Included in this group is the "death cap" (Amanita phalloides) and the "destroying angel" (A. virosa, which superficially resembles common cultivated mushrooms), whose chief toxin is amatoxin.
- Not all mushrooms of the Amanita genus contain amatoxin.
- The monomethylhydrazine group (Gyromitra species) can produce seizures and occasionally death.
- Not all species of Gyromitra have been found to contain the toxin gyromitrin.
- Monomethylhydrazine has been found in Gyromitra esculenta, the "false morel," a mushroom that is occasionally foraged in the Pacific Northwest of the United States.
Symptoms Developing More than 24 Hours After Ingestion
The orelline- and orellanine-containing group (Cortinarius species) causes renal injury.
TOXIC DOSE
- One death cap (Amanita phalloides) can cause death.
- At least 15 to 20 Galerina mushrooms are needed to produce death.
- Ingestion of just a few gastrointestinal-irritant mushrooms can produce marked gastroenteritis.
PATHOPHYSIOLOGY
Cyclopeptide Group
- alpha-Amanitin is primarily responsible for the toxicity seen with the phalloides syndrome.
- alpha-Amanitin binds to nuclear RNA polymerase II of eukaryotic cells and inhibits mRNA synthesis, resulting in cell death.
- The liver and the kidney are the primary targets of alpha-amanitin due to high rates of protein synthesis.
Monomethylhydrazine Group
- Gyromitrin (monomethylhydrazine) causes toxicity similar to isoniazid overdose.
- Both agents deplete pyridoxine (vitamin B6) in the brain, inhibiting production of gamma-aminobutyric acid (GABA) and thereby allowing seizures to occur.
Disulfiram-like Group
Like disulfiram, coprine may inhibit the metabolism of ethanol at the acetaldehyde dehydrogenase step, resulting in an Antabuse-like reaction.
Muscarine Group
- The toxic component is muscarine, which stimulates muscarinic receptors, thereby producing cholinergic syndrome.
- Because of its quaternary configuration, muscarine cannot cross into the CNS; therefore, it causes peripheral cholinergic effects.
Ibotenic Acid and Muscimol Group
- These compounds apparently compete with the normal transmitter, GABA, and cause psychotropic symptoms.
- The peripheral effects, relatively slight, are usually more anticholinergic than cholinergic.
Hallucinogen Group
It is believed that the clinical effects are caused by the indoles such as psilocybin and psilocin, which are chemically related to serotonin.
Gastrointestinal Irritant Group
This group contains many toxins, mostly unidentified.
Orelline- and Orellanine-containing Group
- These heat-stable toxins are chemically related to diquat.
- Poisoning results in tubulo-interstitial nephritis and fibrosis.
EPIDEMIOLOGY
- Poisoning is common.
- The cyclopeptide-containing mushrooms, chiefly Amanita species, are responsible for over 90% of all deaths from mushroom poisoning.
CAUSES
Poisoning usually results from intentional ingestion as food.
Drug and Disease Interactions
An Antabuse-like reaction can be produced by drinking alcohol within a week or two of eating coprine-type mushrooms.
Section Outline:
Diagnosis ⬆ ⬇
[
Show Section Outline]
DIFFERENTIAL DIAGNOSIS
- Diagnosis is based on a history of ingestion combined with clinical presentation and identification of the mushroom (if possible).
- Most poison centers can guide the identification of the mushroom.
SIGNS AND SYMPTOMS
Symptoms Developing Within 3 Hours of Ingestion
Disulfiram-like Group
- Ingestion produces disulfiram reaction: flushing of the face and trunk, palpitations, dyspnea, chest pain, diaphoresis, and hypotension (secondary to vasodilation).
- The reaction may occur after the ingestion of ethanol as long as 1 week after consumption of Coprinus atramentarius.
Muscarine Group
- Ingestion produces cholinergic syndrome: vomiting, miosis, salivation, lacrimation, bronchorrhea, bronchospasm, bradycardia, diarrhea, and urinary retention.
- Seizure may occur in severe cases.
Ibotenic Acid and Muscimol Group
- Ingestion produces alcohol-like intoxication, ataxia, clonus, spontaneous jerking movements, and delirium.
- Seizure and coma may develop in severe cases.
Hallucinogen Group
- In addition to a psychedelic experience, tachycardia, mydriasis, and paresthesia commonly develop; seizure occurs rarely.
- The initial episode lasts 4 to 6 hours; flashbacks may occur.
- In children, fever (102°F to 106°F) may develop with intermittent tonic-clonic seizures.
Gastrointestinal Irritant Group
- Onset of symptoms is usually within 30 minutes to 3 hours of ingestion.
- Response is variable; the same species may cause symptoms in one person at one time and not at another time.
Symptoms Noted More than 6 Hours after Ingestion
Cyclopeptide Group
- Amanita poisoning develops in four stages:
- The first phase is a latent period of 6 to 12 hours and is of diagnostic value.
- Most other poisonous but less harmful mushrooms cause symptoms within 3 hours of ingestion.
- Caution. In mixed mushroom ingestion, symptoms may develop within 3 hours but still contain the deadly Amanita.
- The second, or gastrointestinal, phase begins in 6 to 12 hours and is characterized by nausea, vomiting, abdominal pain, and cholera-like diarrhea with concurrent dehydration; hypoglycemia may develop.
- The third phase is another period of latency.
- Although the patient feels better when the gastrointestinal phase is over, liver injury becomes evident by the rise in ALT, AST, LDH (serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase, and lactic dehydrogenase), and abnormal coagulation studies.
- A rapid fall of coagulation factors usually indicates poor prognosis.
- The fourth, or hepatic, phase follows.
- During this period, fulminant hepatic failure and possibly acute renal failure become clinically apparent.
- The patient may progress to hepatic encephalopathy, coma, and death.
Monomethylhydrazine Group
- Symptoms are usually mild and include vomiting, diarrhea, dizziness, fatigue, and muscle cramps.
- Delirium, coma, and seizures may develop in severe cases.
- Methemoglobinemia and hemolysis may be life threatening.
- Pancreatitis may develop.
Symptoms Developing More than 24 Hours after Ingestion
The orelline and orellanine group produces late-onset nausea, vomiting, oliguria, and renal failure.
PROCEDURES AND LABORATORY TESTS
Essential Tests
Symptoms Developing Within 3 Hours of Ingestion
- No tests are essential.
- Tests to evaluate fluid and electrolyte status should be considered if severe gastroenteritis develops.
Symptoms Developing More than 6 Hours after Ingestion
- If a mycologist is available, stomach contents should be saved for spore identification.
- Serum electrolytes, BUN, creatinine, glucose, and liver function tests should be performed.
- Amatoxin-containing mushrooms may produce fulminant hepatic failure.
- Elevated serum ALT, AST, LDH, and serum bilirubin are the first and best indicators of liver damage.
- Glucose, fibrinogen, and international normalized ratio (INR) or prothrombin levels are the best indicators of liver failure.
Symptoms Developing More than 24 Hours after Ingestion
Serum electrolytes, BUN, and creatinine should be assayed to detect onset of kidney injury.
Recommended Tests
Symptoms Developing Within 3 Hours of Ingestion
- If mushrooms from the gastrointestinal-irritant group are suspected, serum electrolytes, BUN, and creatinine should be followed only if gastrointestinal effects are severe.
Symptoms Developing More than 6 Hours after Ingestion
If Gyromitra species is suspected, methemoglobin levels should be monitored.
Symptoms Developing More than 24 Hours after Ingestion
- Urinalysis reveals concentrated urine with hematuria, protein, and red blood cell casts early, followed by dilute urine with protein and a few casts later in the course.
- Other tests may be available for complicated cases, but should be guided by a mycologist experienced in poisonous mushroom identification.
Not Recommended Tests
Although some mushroom toxins can be measured in blood or urine, none are available for clinical use.
Section Outline:
Treatment ⬆ ⬇
[
Show Section Outline]
- Treatment should focus on decontamination, identification of the mushroom if possible, and intensive supportive care.
- Dose and time of exposure should be determined for all substances involved.
DIRECTING PATIENT COURSE
The health-care provider should call the poison control center when:
- There is any opportunity to identify the mushroom involved; many certified regional poison centers have a mycologist available for difficult cases.
- Toxic effects are present.
- Coingestant, drug interaction, or underlying disease presents an unusual problem.
The patient should be referred to a health-care facility when:
- Attempted suicide or homicide is possible.
- Patient or caregiver seems unreliable.
- Toxic effects are present.
- Coingestant, drug interaction, or underlying disease presents an unusual problem.
Admission Considerations
Inpatient management is warranted if patient exhibits persistent gastrointestinal effect or if symptoms begin after 6 hours.
DECONTAMINATION
Out of Hospital
Although rarely needed, emesis should be considered within 1 hour of ingestion for alert pediatric or adult patients if health-care evaluation will be delayed.
In Hospital
- Gastric lavage should be performed in pediatric (tube size 24-32 French) or adult (tube size 36-42 French) patients presenting within 1 hour of a large ingestion or if serious effects are present.
- One dose of activated charcoal (1-2 g/kg) should be administered without a cathartic if a substantial ingestion has occurred within the previous few hours.
- Amatoxins have been reported to undergo enterohepatic recirculation, and in that case, activated charcoal may be useful for at least 24 hours postingestion.
ANTIDOTES
- There are no proven antidotes for any type of mushroom poisoning.
- Experimental treatments for severe cyclopeptide poisoning include penicillin G, silibinin, thioctic acid, steroids, and hyperbaric oxygen; consultation with a poison center and physician experienced in the care of severe Amanita poisoning is recommended.
ADJUNCTIVE TREATMENT
Symptoms Developing Within 3 Hours of Ingestion
Hallucinogen Group
- Treatment should consist of intensive supportive care.
- Patients who present to the emergency department usually need reassurance only; sedation with benzodiazepines may be necessary.
- See SECTION IV, LSD chapter, for more details on management.
Hypotension (Caused by Any Group)
- Patient should rapidly receive 10 to 20 ml/kg 0.9% saline intravenously and be placed in the Trendelenburg position.
- Further fluid therapy should be guided by central monitoring or right heart catheter to avoid volume overload.
- If hypotension is unresponsive, a vasopressor should be administered.
- Dopamine initial dosage for adults or children is 2 to 5 µg/kg/min, titrated to effect; administration at rates above 20 µg/kg/min is unlikely to provide further benefit.
- If hypotension is unresponsive, norepinephrine should be infused at 0.1 to 0.2 µg/kg/min and titrated to effect.
- High rates of infusion may cause tissue ischemia.
Symptoms Developing More than 6 Hours after Ingestion
Cyclopeptide Group
- Patients with severe effects will need intensive critical care support of liver and kidney function.
- Orthotopic liver transplantation has been performed successfully in some cases of severe phalloides syndrome.
- Exact criteria have not been tested.
- However, consultation with a liver transplantation center is recommended when any of the following signs of poor prognosis are present:
- pH less than 7.3 after fluid resuscitation
- Grade III or IV encephalopathy
- Creatinine above 3.4 mg/dl
- Prothrombin time above 35 to 40 seconds, or rapidly rising
Monomethylhydrazine Group
- Methylene blue should be used to treat symptomatic methemoglobinemia (see SECTION III, Methylene Blue chapter).
- Blood transfusion may be needed for hemolysis.
- Intravenous pyridoxine (5 g) and benzodiazepine should be administered for monomethylhydrazine-induced seizures; pyridoxine dose may be repeated once for recurrent seizures (see SECTION III, Pyridoxine chapter).
Symptoms Developing More than 24 Hours after Ingestion
The orelline/orellanine group may require prolonged monitoring and support of renal function. Preliminary evidence suggests that early hemodialysis or hemoperfusion may reduce kidney injury.
Section Outline:
FollowUp ⬆ ⬇
[
Show Section Outline]
PATIENT MONITORING
Symptoms Developing Within 3 Hours of Ingestion
Electrolytes should be monitored as indicated by clinical course.
Symptoms Developing More than 6 Hours after Ingestion
If signs of liver injury develop, serial electrolytes, and renal and hepatic function tests and continuous cardiac monitoring should be performed.
Symptoms Developing More than 24 Hours after Ingestion
If signs of kidney injury develop, serial electrolytes and renal function tests should be monitored.
EXPECTED COURSE AND PROGNOSIS
Symptoms Developing Within 3 Hours of Ingestion
- Gastrointestinal effects typically peak and abate within a few hours.
- Psychedelic mushroom effects peak and abate within hours, but flashbacks may rarely occur weeks to months later.
- Renal insufficiency induced by volume depletion develops rarely if adequate hydration is provided.
Symptoms Developing More than 6 Hours after Ingestion
- Amanita species ingestion outcome depends on severity of hepatic injury; recovery takes weeks to months and may involve liver transplantation.
- Amatoxin may produce fulminant hepatic and renal failure and death.
- Gyromitrin may produce repeated seizures and hepatorenal failure.
Symptoms Developing More than 24 Hours after Ingestion
Renal failure peaks within several days and slowly improves over weeks, but renal insufficiency may persist.
DISCHARGE CRITERIA/INSTRUCTIONS
Symptoms Developing Within 3 Hours of Ingestion
Patient may be discharged when gastrointestinal or psychedelic effects resolve, and volume depletion is corrected and patient can tolerate fluids.
Symptoms Developing More than 6 Hours after Ingestion
- Patient should not normally be discharged from emergency department.
- Patient may be discharged from hospital when liver and kidney function are stable or clearly improving.
Symptoms Developing More than 24 Hours after Ingestion
Patient may be discharged when kidney function is stable or returning to normal.
PATIENT EDUCATION
Patients should be cautioned to not eat wild mushrooms; even experienced foragers have died from misidentification.
Section Outline:
Pitfalls ⬆ ⬇
[
Show Section Outline]
DIAGNOSIS
- If more than one type of mushroom was eaten, symptoms emerging in less than 3 hours does not assure that cyclopeptide mushrooms were not ingested.
- "Mushroom poisoning" may actually be an allergic reaction or food poisoning.
- "Mushroom poisoning" may actually be a reaction secondary to pesticides sprayed on the mushroom or to edible mushrooms being laced with drugs (e.g., phencyclidine).
- Not all persons ingesting the same species of mushroom will become ill.
- All patients who experience initial symptoms more than 6 hours after ingestion should be presumed to have eaten Amanita phalloides or A. virosa.
TREATMENT
High doses of pyridoxine are known to cause peripheral neuropathy, and excessive use should be avoided.
FOLLOW-UP
Patients who appear to have recovered from their gastrointestinal symptoms when those symptoms developed more than 6 hours postingestion should not be discharged without follow-up.
Section Outline:
Miscellaneous ⬆
ICD-9-CM 988.1Toxic effect of noxious substances eaten as food: mushrooms.
See Also: SECTION II, Hypotension and Seizures chapters; SECTION III, Methylene Blue and Pyridoxine chapters; and SECTION IV, Disulfiram and LSD chapters.
RECOMMENDED READING
Goldfrank LR. Mushrooms: toxic and hallucinogenic. In: Goldfrank LR, Flomenbaum NE, Lewin NA, et al., eds. Goldfrank's toxicologic emergencies, 6th ed. Norwalk, CT: Appleton & Lange, 1998.
Author: Luke Yip
Reviewer: Richard C. Dart